CurtPalme.com Home Theater Forum

[redfox001]

I could only do this superficial test quick. Using the same neckboards is better but I have to mod neckboards for that. Might try it but I remember Barclay testing the old neckboards with lug and lcp and he said lug was to dimm. Might find the topic back.

[redfox001]

[redfox001]

Oh by the way I can also confirm that the noise that runs on the screen is gone with the 9518lc.

[mp20748]

[mp20748]

[mp20748]

[mp20748]

These are quick and dirty shots showing the work I've done on an older set of Electrohome neck boards to match them to LUG's specifically. Before working on the VDC newer neck boards and using them until today, my setup basically set for awhile, because even a set of my modified Electrohome neck boards were not enough to get the level of sharpness of the LUG's in my 9518 I'm used to.

I'll eventually dial the set in better and do more shots. Just thought the improvements were even worth posting them as-is even before anything is done to the PJ.

The light at the bottom of the images is light bleeding through a painted slider door.

[tschaeikaei]

[redfox001]

Ok I think you mean maximising contrast. With contrast I look at the maximum where there is no blooming or other strange stuff than I put up a 100 ire windowed testpattern and measure the light. If I am above 11 ftL I lower because I do not want to wear the tubes to fast. So not very helpfull I am afraid?

The brightness should be set using a testpattern with several grades of black and the one with 16 should be just visible. Set brightness at 50 and use g2 to get there. At the end of the calibration my brightness is 50 but sometimes I change a little after.

[mp20748]

I had mentioned in this thread that I had tuned a set of the older Marquee neck boards to the LUG tubes in my latest Marquee. The screenshot above are after I made those changes. The changes are me using my pattern generator and some of its known test patterns to better match what I'm used to seeing on the LCP's.

My initial impression of the LUG's when I first got this projector was a not so sharp image when used with the older Electrohome (modified) neck boards. That was the first thing I noticed, with the second thing that jumped out at me was a more laid-back image that seem to require a more intense drive to produce the same or similar punch I'm used to.

The newer VDC neck boards greatly improved on the focus, but had other issues. It wasn't able to drive the tubes the way I'm used to with the LCP's.

So what I did using my pattern generator was better align the older Electrohome neck boards with the LUG's and that made for better focus and greatly improved drive. And that may be seen in my posted screenshots above In this thread.


I've since went one further after Barclay posted somewhere on the HK grid in the LUG's, an enlightenment that took me back to the bench. My previous thought on the HK grid is that is was simply some form of static grid, to then find out by looking into my red CRT myself, that it is a full grid element in the CRT itself. So from there, I'm back in my shop as soon as things got really quiet around here.


And after looking at everything in the manuals, I found that the document that Barclay posted showed the HK grid requiring an 1 meg resistor to ground. Looking at the Barco 909 manual, they followed that document with an 1 meg to ground. I then looked at the Sony G90. It used an 10 meg to ground while both VDC and Electrohome's were using the 330K that was just a pin hold-down resistor for a not use pin in the LCP design.

So my first move or change was going from the 330K to an 2.61 meg resistor to ground on my Marquee with the LUG's. The changes were very noticeable and it was an improvement over the above shots. But before starting on this Barclay suggested a range of resistors to try. I didn't feel a need to go below 1 meg or try the 1 meg at that point, so the 2.61 meg was it. All until I put 4.7 meg's in yesterday..WOW Not sure if it can be seen in my latest screenshots in the screeenshot thread, but boy was that a change for the better.

I like the word sharper, but think much tighter and sharper would be better. And, I still have a ways to go before the 10 meg change..

[redfox001]

Ok the note in the doc barclay posted says the lug 3pf is correct when over 1 MOhm 1/2 watt is used on the KH grid. They mention 1/2 watt but do not think there is 1/2 watt current going to that grid so perhaps the 1/2 watt for other reasons? Did you try different watt resistors?

[mp20748]

[haireez]

Mike,

Please update us if you manage to get the best solution to modified VNB that could drive lug tubes on Marquee. I might try to get lug tubes to install on my vision 1. Do we need to get 909 yokes as well for best results?

[mp20748]

[greg9518lc]

[thewolfman]

[cmjohnson]

Be aware that the 909 focus coils are designed by Kanto-Denshi to be part of a complete SYSTEM, consisting of both the
deflection yoke and the focus yoke.

There is a substantial difference in the relative lengths and positions of Thomson deflection and focus yokes as compared to Kanto-Denshi (Barco) deflection and focus yokes.

This is PROBABLY the reason why Frankenyokes are often problematic, simply because the longer Thomson deflection yoke forces
the K-D focus yoke to be set back almost an inch farther back on the tube neck than it was designed to be placed.

The obvious answer to this problem is to investigate the possibility of retrofitting the K-D deflection yokes to the Marquee AS WELL
as the focus yoke.

But that is far from a plug and play operation requiring only a few wires to be swapped around in the connector.

While adapting the focus yoke requires changing the wiring harness, and then to truly optimize it you have to adjust some
component values in the resonant drive circuits on the focus board, making changes to the deflection yoke is a somewhat
deeper kettle of fish.

While the Thomson and K-D deflection yokes have the same deflection windings, they're connected differently and
thus you have to do some serious re-engineering just to get all the wires rearranged and all plumbed in to suitable terminal strips
for connection to the new wiring harness.

I found that to rewire a K-D deflection yoke just to be mechanically suitable for Marquee use, you will have to gut the Thomson
deflection yoke (and convergence coil) assembly of all three of its terminal strips and glue them to the K-D yoke after removing
its own unique type of terminal strip, which doesn't have the space or the number of contacts needed for the change.

And after all that is done, after you've ensured that you've got every coil wired correctly to its mate, after you have separated
the left and right half coils for H deflection, at their middle connection point, so as to make them electrically separate like the
Thomson yoke is, after all that you then have to look at the inductance values and start figuring out how to adapt the drive
capacitance values on the HDM to restore resonance to THAT circuit as well.

I've made a start at this. I have NOT finished the first prototype yet.

What's the light at the end of the tunnel? Barco rates the 909 for 3200x2560 resolution with LUG tubes. With the RIGHT
magnetics, and PROPERLY adapted drive circuits, there is absolutely no reason at all why a Marquee equipped with the same
LUG tubes can't get the same performance as the 909.

So it's worth some effort to achieve.

[Tim in Phoenix]

[cmjohnson]

The 909 deflection yokes have the same windings, wind for wind, as the Thomson yokes, but they are connected differently
and that has to be changed in the rewiring.

The Thomson yoke has two separated H windings, and each of them presents two separate connections to the HDM, so that
these two separate coils can be connected either in series or in parallel via the HDM's switching relays.

The K-D deflection yoke also has two separate H windings, but they are soldered together at one point, creating what
is best described as a Y configuration with a common terminal for both windings. That center connection has to be undone
and then both windings can be brought out to four terminal points like the Thomson deflection yoke.

[thewolfman]